论文标题
空间等离子体中低βα/质子梁的电磁不稳定性
Electromagnetic instabilities of low-beta alpha/proton beams in space plasmas
论文作者
论文摘要
不同物种或颗粒种群之间的相对漂移是太阳等离子体流出的特征，例如，在太阳风，冠状质量弹出和星际间冲击的快速流中。本文表征了在没有任何固有的热各向异性的情况下，低βα/质子漂移的分散和稳定性，通常被调用以刺激各种不稳定性。此处得出的分散关系描述了不稳定性的全部范围及其与传播角度和等离子体参数的变化。结果揭示了电磁质子回旋子和α壳模式的不稳定性之间的潜在竞争。对于特定于低β太阳风的条件，例如，在外电晕的低地中心距离下，不稳定性在α回旋子分支上运行。 （平行）等离子体β和/或α-普罗替子温度比系统刺激了Alpha Cyclotron模式的生长速率。因此，即使在没有温度各向异性的情况下，也可以期望这种不稳定性也会发展，并有可能对观察到的α颗粒漂移的自洽调节。
Relative drifts between different species or particle populations are characteristic to solar plasma outflows, e.g., in the fast streams of the solar winds, coronal mass ejections and interplanetary shocks. This paper characterizes the dispersion and stability of the low-beta alpha/proton drifts in the absence of any intrinsic thermal anisotropies, which are usually invoked in order to stimulate various instabilities. The dispersion relations derived here describe the full spectrum of instabilities and their variations with the angle of propagation and plasma parameters. The results unveil a potential competition between instabilities of the electromagnetic proton cyclotron and alpha cyclotron modes. For conditions specific to a low-beta solar wind, e.g., at low heliocentric distances in the outer corona, the instability operates on the alpha cyclotron branch. The growth rates of the alpha cyclotron mode are systematically stimulated by the (parallel) plasma beta and/or the alpha-proton temperature ratio. One can therefore expect that this instability develops even in the absence of temperature anisotropies, with potential to contribute to a self-consistent regulation of the observed drift of alpha particles.
